Cap for a writing instrument



FIG. 1 is a top, right side perspective view of a cap for a writing instrument according to the present invention;

FIG. 2 is a front elevational view of the cap of FIG. 1;

FIG. 3 is a right side elevational view of the cap of FIG. 1;

FIG. 4 is a rear elevational view of the cap of FIG. 1;

FIG. 5 is a bottom plan view of the cap of FIG. 1; and,

FIG. 6 is a top plan view of the cap of FIG. 1. 

The ornamental design for a cap for a writing instrument, as shown and described. 